Motor control and phasing



July 15, 1941. M. POTTS MOTOR common AND PHA s'mG Original Fil ed July3, 1937 2 snaps-sheet 1-- LOUIS M. POTTS (Ittomeg July 15, 1941.

L. M. Po'r'rs v MOTOR CONTROL PHASING 2 Sheets-Sheet 2 Driginal FiledJul 's, 71937 mnu ttorneg :Patenteciilul y -15,1941

, UNITED STATES PATE NT OFFICE MOTOR coN'rnor. AND rnssmG Louis M.Potts, Evanston, 11]., assignor to 'l'eletype Corporation, Chicago,11]., a corporation of Delaware Original application mm, 1937, SerialNo.

151,827. Divided and this 17, 1939, Serial No..262,345

application March as Ciaims (01. 178-695) The present invention pertainsto telegraphic communication systems and more particularly to telegraphsystems involving a' plurality of sub- I stations arranged upon aplurality of radial lines which connect a central ofllce with thesubstations which ar provided with telegraph apparatus having a drivingmotor normally inert.-

substations such that a substation motor is v started into operation inresponse to seizure of its connecting line bythe central ofliceswitching equipment and in which synchronous motors may be started by analternating current of low fre quency which is increased to the fulloperating frequency of the motor, the motor beingthereafter maintainedin synchronism by a continuous alternating current supplied over a powersircult orsynchronizing circuit which is operatively independent ofcommunication signals. I

Further features reside in provision of means for restarting substationmotors automatically, should they have been stopped, in the provision ofauxiliary means for supplying power to the substation motor, and in theprovision of starting means changeable dependently upon increasing speedof the motor to synchronizing speed.

'I'hese objects and features are attained by supplying at the centraloflice'embodied in interconnective devices asource ofaltematlng currentwhich supplies the synchronizing power over a power conductoror over thecommunication conductor or over phantom or composited circuits after acommunication condition has been estabconnected to output conductors ofa generator I Y the line jack and plug, a polyphase current com- 4lished and overvarious circuits in the steps of progress towardestablishment of the communication condition, and by providing furthermeans in the connective equipment at the central oflice for supplying analternating current of varied frequency, this further means also beingoperative to supply to a line a polyphase current comprising a series ofimpulses of alternating polarities and of increasing frequencyinresponse to seizureof the line for communication purposes.

' This application is a division of U; S. Patent No. 2,237,951, issuedApri1i8, 1941 to L. M. Potts.

A more completeunderstanding oi the invention will be obtained from thefollowing descrip-' alternating current source II tion taken inconnection with the accompanying drawings, in which Fig. 1 illustrates acomplete equipment of onecentral oflice connective unit associated withtwo.

Fig. 1.

In Fig. 1, a connective pair of plugs I and 2 are connected forcommunication through a repeater relay set 3 when relays I and I areenergized, and the circuits of the connective plugs also includeinductive association with a source of alternating current whenconnective relays l and i are energized. Prior to energizatlon oi relaysI and 6 respectively, the switching plugs I and I are which normally isat rest, but which is energized to start into rotation when plug I orplug 2 is inserted into a line jack such as I. The generator 1 thendelivers to line conductors associated with prising two concurrentseries of alternating cur-j rent impulses generated by its commutator I.the frequency of which increases as the speed or the generator 1increases, until this increasing frequency attains the frequency oi thealternating current source II alter which relay I is operated to switchthe conductors of plug I through to the and to the repeating relay setI. 4

. At substation II. a synchronous motor .I! is provided with acentrifugal device II having a switch It with a plurality of contactswhich are shownincontactual relations or their condition of rest. Thecentrifugal device has also'a cam \tion code signal transmitter issymbolized at I], a calling key is illustrated at II. and a condenser Isis included in an alternating current to prevent operation the minisubstation asis provided with a swit hing power circuit ofmotor is ofseries relay winding Ill.-

At the central oflice, munication line iii jack 8 and a signaling linerelay :2 which has I of the system.

Generator 1 comprises a self-starting alternating current motor 3|having heel32 to retard acceleration and centrifugal device 33 similarto device |3 which controls a centrifugal switch 34 to'energize a signallamp 35. Motor 3| is supplied with power from a source 35 under controlof an armature 31 of relay 38 energized by control of sleeve relay 38which is responsive over an obvious circuit to insertion of plug 1 intojack 8.

Variable generator 1 has output conductors 4| and 42 connectedrespectively to outer ring 43 and inner ring 44 of the commutator 9.Positive battery 45 and negative battery 46 supply current to thecommutator 9 which by insulated brushes 41 and 48, carried by arms onmotor shaft 49, connects the said batteries in sequential manner to theoutput conductors 4|, 42 by engagement with the-short commutatorsegments 52, 53, and 54. When the commutator brushes are in positionsshown, a circuit path will be formed through positive battery '45,segment 5|, brush 48, ring 44, and conductor 42. When brushes 41 and 48shall have'moved through an angle of 45,

brush 48 will disengage from the segmentil and is as follows: Anoperator at substation desirwill rest upon an isolated segment whilebrush 41 will engage segment 5| to form a circuit path through'positivebattery 45,.segment 5|, brush 41, ,rin 43, and conductor 4 I When thebrushes shall have moved 90 from the position shown, brush 48 willengage segment 52 forming a circuit path through negative battery 48,segment 52, brush 48, ring 44, and conductor 42. When the brushes shallhave moved 135 from the position shown, brush41 will engage segment 52forming a circuit path through negative battery 45, segment 52, brush41, ring 43, and conductor 4|. This sequence of four electrical.impulses will be repeated .through segments 53 and 54 resulting inrepeated cycles each comprising a positive impulse on conductor 42followed by a positive impulse on conductor 4| followed by a negativeimpulse on conductor 42 followed by a negative impulse on a conductor4|, completing the cycle.

lamp 35 glows when motor 3| is rotating at any speed. Shaft 49 carries aworm 8| engaging a gear 52 upon a snail 53 whose follower 54,pivstructure having four polar field faces with four windings connectedserially in pairs.- Mounted on the rotor shaft 1| is a centrifugaldevice l3 controlling a switch l4 which comprises contact members 12 to18 inclusive, and having furthera rotary cam 11 controlling a switch IS.A correcting circuit including grounded battery, resistor 18, winding ofrelay 22, contact of relay 24, line conductor 2|, contact members 13,14, cam switch l5 when closed, and two field windings of motor l2, willsupply tomotor- |2 a current sufficient to turn the rotor into thatangular position wherein cam 11 opens cam switch l5, thus interruptingthe described circuit. Cam switch |5 determines the angularstopping'position of the rotor, thereby efiecting its purpose of openingthe line 2| after removal of plug I from jack 8 so that key |8 may beused for signaling.

An operator key 8| is connected to include into the communicativecircuitof the plugs and 2 an operators set comprising recorder 82 andtransmitter 83. During a connection between two lines, slow-to-releaserelays 84 and 85 hold their armatures attracted in response to signalingcurrents of communicative nature through the plugs and 2. Inductioncoils having primary windings connected to a common alternating currentsource |8have also secondary windings 88, 89, which supply alternatingcurrent to the circuits of the lines connected to plugs and 2 for thepurpose of synchronizing and driving substation motors |2 over circuitsto be described.

' Operation of the structure illustrated in Fig. 1

ing to transmit a message to a substation on line connected to line jack85 will operate the calling key l8 to close a calling circuit includinggrounded battery, resistor 18, winding of relay 22, contacts of relay24, line conductor 2|, key I8,

2| for transmission'purposcs. Relay 38 ener gizes, and by its armaturecontacts energizes relay- 38 'over an obvious circuit. Relay 38 attractsits armatures and armature I84 energizes snail magnet 51 overan obviouscircuit while armature 31 closes analtemating current power circuit formotor 3| which begins to rotate andcontinuesrotation with increasingspeed.

Soon afterbegin'ning of rotation, centrifugal switch 34 closes anenergizing circuit for lamp 35. Generator 1 now' supplies a varyingpolyphase current comprising alternating potentials of increasingfrequencies to the output conductors 4!, 42, which now supply current tomotor I! over two paths as follows: With brushes 41, 48

in position shown, a circuit path extends from positive battery 45,through segment-5|, brush 48, ring 44, output conductor 42, armature I88,of relay 5, ring members of plug and jack 8, line conductor-2|, andswitch contacts 13, 14 to the open cam contact I5. Brushes 41 and 48 maystart from any angular position of shaft 48. When brushes 41- and 48reach a position 45 clockwise from the position shown, a circuit isformed from positive battery 45, through segment 5|, brush 41, ring 43,output conductor 4|,

back contact and armature "5 of relay 5, line winding I48 of relay 38,tip members of plug and jack 8, line conductor I81, contact members 15,15, and two field windings of motor |2 to ground, energizing motor l2 toturn its rotor through90", thus closing cam. switch [5. This is followedby current over a circuit including negative battery '45, segment 52,brush 48, ring 44, output conductor 42, back contact and armature I88 ofrelay 5, ring members of plug and jack 8, line conductor 2|, contactmembers 13. 14,

motor I2 to-ground, energizing motor I2 to'turn its rotor a further 90".Further rotation of the brushes of commutator 8 form a circuit fromnegative'battery 46, segment 52,.brush 41, ring 48, output conductor 4|,back contact and armature I85 01' relay 5, line winding I88 of relay 88,tip. members of plug- Iand jack 8, line con- I 2,249,435 closed camcontacts I5, and two field windings of ductor I81, contact members 15,18 and twofleld windings of motor I2 to ground, energizing motor I2. toturn its rotor through an additional This is followed by current over acircuit including positive battery 45, segment 53, brush 48, ring 44,output conductor 42, armature I88 oi. relay 5, ring members ofplug landjack 8,- vline conductor 2|, contact members 13, 14, closed cam switchI5, since cam I1 now is 90 from its operating angle, and two fieldwindings of motor I2 to ground, producing a field magnetization. inmotor I2 which will advance the rotor a further 90 completing onerevolutionof the motor I2.

In the second half of the revolution of commutator 8, segments 53 and 54cooperate with brushes 41 and 48 torepeat impulses of reversing polarityover conductors 4| and 42 and line conductors I81and 2| to repeat thecycle of the rotor of motor I2 and this cycle of polyphase motorstarting current is repeated with increasing frequency until thefrequency of currents upon conductors, 42 equals or exceeds thefrequency of currents obtainable from source of alternating currentpower III, and the speed of rotation of motor I2 equals or exceeds thespeed obtainable from the alternating current power source I8.

Should the brushes of generator 1 start from any position other than theposition shown, the

described starting of motor I2 will be delayed by a fraction of a cycleonly.

As the speed or the rotor of motor I2 approaches the speed of the.altemating current power source III, the centrifugal device I3 willoperate its switch I4 to reverse the contactual relations of contactmembers 12 to .15 and will 'remove cam 11 from engagement with switch Ias illustrated in dotted line in Fig. 4. By reversal of contact members12 to 18, an alternating current power circuit for continuous running ofmotor I2 is set up including batteries 45 and 48 in alternation,segments 5|, 52, 53 and '54 in rotation, brush 41, ring 43, outputconductor 4|, back contact and armature I85 of relay 5, line winding I85of relay 38, tip of plug I, short spring of jack 8, line conductor I81,condenser I8, and two field windings of motor I2 to ground. Remainingwindings of motor I2 are not used after starting, their circuit pathbeing open at contact 14.

At the same time, by theoperation of centrifugal switch I4, atelegraphic signaling path is formed including batteries 45 and 48- inaltemation, segments 5|, 52, 53, and 54 in rotation,

brush 48, ring 44, output conductor 42, back.

contact and armature I88 01' relay 5, ring of armature II 5 and contactof relay I I I, winding of relay 5, and back contact and armature ofunenergized relay 84 to ground. Relay 5operates its armature I22 tointerrupt the energizing circuit of relay 88 while its armature I88forms an energizing circuit for slow-to-operate relay 84, the relay 38releasing quickly to close an alternative ground connection througharmature I23 for the described circuit of the winding of relay5 beforethe slow-to-operate relay 84 has operated its armature to interrupt theoriginal energizing ground contact just described for. relay 5... Also,by its armature I24, deenergizedrelay 88 forms a holding circuit forrelay III including grounded battery, resistor II2, winding and contactsof energized relay III, armature I24 and ground. Also, by release or itsarmature I84, relay 88 interrupts the energizing circuit of snail magnet81 causing release of pivoted armature 58 which withdraws snail follower84 from snail 88 whereupon the follower is restored by permits contactmembers 88 to separate. Also, by release of its armature'fl, relay 88interrupts the power circuit of motor 8|, the motor stops and lamp 35 isextinguished, thus placing generator 1 in condition to operate againinsertion of plug 2 into jack 85.

By energization of relay 5, a definitive alternating current powercircuit has been formed for motor I2 including grounded battery-HI,induction coil winding 88, front-contact and armature I85, line windingI88 of relay 38, tip members of plug I and jack 8', line conductor I81,condenser in response to I9, and two windings of motor I2 to ground. No

direct current flows because of condenser I9 hence relay 38 isnotenergized. A definitive telegraphic communication circuit also has beenformed by the operation of relay 5 including grounded battery, resistorI32, windin of repeating relay I38, coutact and armature ofenergized-repeating relay I34, contacts of operator key 8|, winding ofrelay 84, front contact and armature I88,'ring members of plug I andjack 8, line conductor 2|, contact members 13, 12, selector magnets I5of a recording receiver and contacts of permutation transmitter I1 toground. In this circuit, a central oflice operator may includemagnets 82of, a

, recording receiver and contacts 88 of a permutaplug I, long spring ofjack 8, line conductor 2|,

switch contacts 18, 12, telegraph receiver magnets I8 and telegraphtransmitter I1 ,to ground. The

j telegraph receiver I8 may operate irregularly,

Soon thereafter, snail follower 54 engages and closes snail contactmembers 88, thus completing a circuit for energization of snail'relayIII inclutiing grounded battery and resistor II2, winding' of relay III,armature 8 of energized relay 88, and contact members 88 to ground.Relay III operates its armatures and energizes relay 5 over a-circuitincluding battery and resistor I I4,

and armature oienergized relay I38, resistor I38, g and armature I88 ofunenergized relay 6 to' ground. In the circuits of the repeating relayset 3 as now established, energization of relay 5 interrupts thedescribed preliminary energizing circuit of relay I83-and substitutesthe geflnitive telegraphic. communication circuit ascribed above.v Thecentral oiiice operator, having operated key 8|, having communicatedwith calling substation II, and having-ascertained that the operator atsubstation II desires tobe connected to line 84, now establishes theconnection by lnserting plug 2 in line Jack 85, which results inenergizing relays I4I' and I42 over the-sleeve cir-- cuit of jack s5.Operation of thearmature or its spring and associated with jack 95. Inresponse to this starting currentof varied frequency, the motor at thesubstation I5I is started and operates its centrifugal devicecorresponding to I3 of sub- Snail follower 54 closes snail constationII. tacts 68, thus completing a circuit through armature I52 of relayI43 to energize snail relay I53 whose armature I54 responsively closes acircuit through grounded battery, resistor I55, armature I54 of relayI53, winding of relay 6, and armature of relay 85 to ground to energizerelay 6, which by armature I39 opens the described.

preliminary energizing. circuit of repeating relay I34, by armature I51.interrupts the energizing circuit of relay I43, and by back contacts andarmatures I48, I41 interrupts the circuits of output conductors H, 42 ofgenerator 1, while by front contact and armature I45, it forms a definitive alternating current power circuit including grounded battery I58,induction coil secondary winding 89, front contact and armature I48 ofrelay 5, winding I48 of relay I43, tip-of plug 2, short spring of jack95, line conductor I59 to substation I5I, and through condenser andmotor to ground as in substation II, and by front contact and armatureI41, the relay'5 forms a definitive telegraph communication circuitincluding grounded battery, resistor I31, winding of re- I peating relayI34, contacts of energized repeating relay I33, winding ofslow-to-ope'rate relay 85, front contact and armature I41, ring of plug2,

long spring of jack 95, line conductor 94 to substation I5I and throughreceiving and recording apparatus to ground as in substation II.

Armature I51 deenergizes relay .I43, armature I48 supplies alternatingcurrent but does not energize-relay I43 to hold itsarmatures. Accordorboth of them for any cause as by a line fault become out of phase withits power source I0 or for any other reason come to rest, or if themotor should slow down to a speed below that necessary to keep thecentriflugal device I3 operated, contacts 15, 18 will shunt thecondenser I9. This will permit direct current from battery I3I to flowthrough the power circuit described, resulting in energization of relay38 to attract its armatures which will set up the starting conditions ofgenerator I withrelease of relay 5, so that output conductors 4|, 42again will deliver to motor I2 polyphase currents of increasingfrequency to bring the motor again into phasing speed with the source I0when the centrifugal device I3 and the snail contact 68 again willfunction to energize relay 5 or 5 and deenergize which there also areprovided collecting rings connected to a further synchronous winding asillustrated in Fig. 3. Direct current for starting the motor istransmitted oyerthe two sides of the line in parallel and subsequentlyalternating current is transmitted over the two sides of the' line inparallel for driving and synchronizing, while. telegraphic signalingcurrent is transmitted over the two conductors of the line looped inseries.

At the substations 200 and 284, the motor "I comprises a permanentmagnetic field and a rotor 202 having a distributed winding connected toa segmented commutator 203. 'Collectingrings 204 are connected to afurther winding in the rotor. A centrifugal switch 205 operates when themotor is substantially at synchronous speed with source 255 and containsswitching eleingly, relay I43 releases its armatures. Armature Iprovides ground for the'winding of relay 5 before slow-to-operate relay85 Ope -S its ground connection, armature I8I forms a holding circuitforrelay I53, while armatures I44, I45, open their circuits to deenergizemotor 3| and snail magnet 51, thus stopping the motor 3|, extinguishinglamp 35 and restoring arm 54.

The two substations, both illustrated by details shown in substation II,are now in communication over the circuits described by means ofrepeating relay set 3, and the motors thereof are maintained at exactspeed by currents derived from alternating source I3 and distributed tothe substations over the described alternating current power circuits.

Relays 84 and I34 now are energized by communication signaling currentsof marking nature flowing to substation II through jack 8, while relays85 and. I33 areenergized by similar currents through jack 95. Relays 24,39, MI, and I42 are held energized by sleeve circuits of plugs I and 2.Relays 5 and 8 are held energized by individual holding circuits undercontrol of contacts in unenergized relays 38' and" I43 respectively.

Means is provided for restarting automatically a stoppedsubstation-motor during communicaments 205 to 2I0 whichoontrolsubstation circuits for line conductors 2H and 2I2. In the illustratednormal position of the centrifugal switch, assumed when the motor isinert, line conductor 2 is connected through winding 2I3 of relay 2,switching element 201 and commutator 203to ground. Line conductor 2I2 isopen to direct currents.

- Line conductors 2H and 2I2 -are'connected through condensers 2I5 and2I5 to brushes of collecting rings 204. A manual key 2" serves tocontrol signal devices at a central ofllce or switchline 2I I, 2I2comprises a jack 225, a cut-ofi relay 221, a calling line relay 228, anda calling line lamp 229. A pair of connective plugs 23I, 232 areassociated together for communication through double wound relays 233,234, slow-torelease relays 235, 235, and a repeating relay set 238;comprising repeating relays 239, 240, resistors 24I, 2 42, 243, 244, andgrounded batteries 245, 245.

tive condition. Should either substation motor Sleeve relays 35I and 252are includedin sleeve circuits of plugs 23l and 232'respectively. Armature members of relays 233 and 234 are associated throughrepeatingcoils253 and 254, respectively, with an alternating current power source 255having a frequency higher than baud value of permutation codetransmission and windings of the same induction coils are includedinpower circuits and telegraphic communication circuits may be switchedinto circuits of the plug pair 23| 232 by means of manual. key 251.Resistor 258 balances against the operators set 255, resistor 253balances against repeating relay 233, and resistor 250 balances againstrepeating relay 240. A second substation line 25l, 252 is indicated inassociation with jack 253 and substation 254 to duplicate the substation200. Preparatory energizations of repeating relays 233 and 240 areefiected for relay 240 by current over a circuit 255 including .groundedbattery 245, resistor 2,

T liefore-break-armatures and long contact memto be described. Anoperator's telegraph set 255,

winding of repeating relay 233, contact and armature of. energizedrepeating relay 240, contacts of manual key 251, resistor 255, circuitconductor 255, back contact and armature of sleeve relay l, and ground,and for relay 233 over a companion circuit 255 including ounded battery245, resistor 242', windlng'of repeating relay-240, contact andarmatureoi'energ'lzed repeating relay 233, resistor 251, circuit conductor 255,back contact and armature of relay 252, and ground. Operation of thestructure of Fig. 2 is as folhas of operated relay 233, both windings ofrelay 233, tip and ring .of plug 23 I, both springs of jack 226-, andboth line conductors 2| I. and 2 l2 to junctions 211, 218 respectivelyat substation 2 00, ex-

tending thence for alternating currents through condensers 2| 5, 2|6,collecting rings 204 and ground, and extending for direct currents fromjunction 211, through an energizing-winding 2|3 of relay 2 l4, contactand switch member 201 and commutator 203 to ground, also from junction218, through contacts of energized relay 2|4, switch contacts 2|0, 203,=winding 213 of .relay 2, contact and switch member 201 and com-' mutator203 to ground. Direct currents start the rotor 202 and drive itwithincreasing speed until synchronlsm with source 255, through in-'duction coil winding215, is approximated whereupon torque derived fromalternating currents through rings 204 will supplement torque derivedfrom direct-current through commutator 2 03, the rotor will attainsynchronism, and centrifugal 4 switch 205 will due to its Ipredetermined speed adjustment, be operated.

Operation of centrifugal switch 205. removes all conductive ground fordirect current from line conductors 2| I, 2|2 at substation 200,whereupon direct current ceases in windings of relays M4 and 233 andthose relays are deenergized, resulting in establishment of a firstcommunication circuit and of definitivemarallel alternating lows: Anoperator at substation 200 closes the manual key 2" thereby energizingsignal lamp relay 223 over a calling circuit including grounded battery,resistor, winding of line relay 228, contacts ofcut-oilf relay 221, lineconductor 2|2, key

2" and ground, Contacts of energized relay 228 cause illumination oflamp 223 over an obvious circuit.

An operator at the central ofiice 225 awaits cessation of theillumination of lamp 223, then inserts plug 23| into jack 225,energizing sleeve relay 25| and cut-oil! relay 221 over an obviouscircuit. Energization oi sleeverelay 25| opens circuit 255 and, therebyinterrupts the described preparatory energization; of repeating relay233 whose deenergization changes the energizing circuit of repeatingrelay 240 from the described preparatory circuit 255 to a holdingcircuit includingground, resistor, winding of repeating relay 240,make-beIore-break contacts oi deenergized repeating relay 233, resistor244, and ground.

Insertion of plug 23| also results in energization of relays 2, 2 ,3,235, and reenergization" of relay 233 over a line circuit of firstresponse including grounded battery, resistor 24|,'winding of repeatingrelay 233, contact and armatureof energized repeating relay 240,contacts of manual 7 key 251, induction coil winding 2", winding 212 ofrelay 235, make-before-break contacts of relay 233, winding 213of-lrelay 233, tip or plug 23|, short spring of jack .225, lineconductor 2| I,

current power circuits. Thelfirst communication circuit includesgrounded battery 245, resistor 24l, winding of repeating relay 233,contact and armature member of repeating relay 240, contacts of manualkey 251, induction coil winding 2n, winding 212 oi. relay :35,makebefore-break contactsand winding 213 of relay 233, tip of plug 23|,short spring ofjack 226, line conductor 2| junction 1 211, windings oiselector. magnet 2|5, contacts of .code transmitter -2|3, break key 230,centrifugal switch member 208 Y fand its long-contact spring 210,contact and switch member 205, junction 218, line conductor 2|2, longspring of jack 225, ring of plug 23|,

winding 28l'and make-berore-break contacts oi.

relay'233, winding'282 of relay 235, resistor 253 (to balance winding ofrelay 233) closed contacts 285 of manual key 251, induction coil windingwinding 2|3 of relay 2", contact and switchmember 251, commutator 203,and ground. Op-.-

eration of relays 2|4 and 233 interrupt the: described line circuit offirst response and substitute two parallel motor starting circuits eachcarrying direct current from-battery 214 asa' souce ofmotor startingcurrent and carrying also alternating current from induction coilwinding 215 as asiource of motor synchronizing current; The

' r paralleLmgqtr starting circuits extend for both classes ofcurreiit'i'rom ground, through battery- 214, induction coil winding215,both ofthe makeis operated.

283, and ground. Difierential relay 2331s not en-v make-before-breakcontacts of deenergized relay '233, windings of relay 233, tip and ringelements of plug 23| and jack 225, line conductors 2| I and- .2l2,condensers 2|5 and 2|5, then uniting and continuing through' collectingrings 204 to ground. -Relay 233 is magnetized to an insurficient degreeby the transmitted alternating power current, and its armature membersare not .The paths ior alternating current constitute aphantom channelupon the line 2|,l-2|2 which is operatively independent of transmissionoitelproduce a spacing telegraphic signal while maintaining the powercircuit efiectively unchanged. Resistor 233 is included in series inone-side of the phantom circuit of plug 231 to balance resistor 231 andwinding of relay 233 in the other side of the phantom circuit of plug231, while resistor 233 is included in series in one side of the phantomcircuit of plug 232 to balance resistor 232 and winding of relay 233 inthe other side of the phantom circuit of plug 232.. When manual key 251is operated to include operators set 253 and its selector magnet 233 inthe telegraph communication circuit and, .therefore, in one side of thephantom circuit of plug 231, its contacts 233 open a shuntthereby toinclude a balancing resistor 253 in theother side of the phantom circuitof plug 231 to maintain balance between the two sides and then whentransmitting relay 233 is operated with key-251 in reversed condition, aresistor 233 to ground is substituted for winding of relay 233, resistor231, and battery 233 to ground.

Having inserted plug a1 into Jack in manual response to illumination ofsignal lamp 223, a

switching operator awaits illumination of signal lamp 233 which will notbecome energized until after the connected substation motor 231 hasattained its synchronous speed with resultant deenergization of relay233 and energization o1 relay 233. Key 231 then may be operated, thusconnecting set 233 and substation 233 for communication, and theswitching operator may complete a communicative connection between twosubstations by inserting plug 232 into any substation Jack 233. After acycleof operation to start the motor at substation 233, relay 233 willbe energized and lamp 231 will be illuminated, the two lamps 233 and 231then functioning to advise the switching operator that the twosubstations 2 33 and 233 are connected and conditioned forcommunication. Either station may operate a break key 233ito controlrelay 235 or 233 to flash I attract attention of the operator.

Referring 3, a structure is disclosed in gize the substation motor andin which the local lamp 233 ,or 231 intermittently to 2, a4a,4ss

member an and electrical switch :09 which is,

operated when the motor reaches its synchronous speed and remainsoperated throughout the ensuing communication. A motor control relay 310has its contact and armature connected in the local power circuit of themotorand when energized, closes the circuit of the local current.

winding of the rotor. Line conductors 311 and 312 are connected throughcondensers 313 and 313 to winding of relay 313 and through centrifugalswitch 333 and its contact to ground.

Selector magnets 315 representing a recording receiver and contacts 313representing a code signal transmitter are bridged permanently fromconductor 311 to conductor 312; A manual calling key 311 is connectedbetween conductor 312 and ground. A break key 313 is provided.

At the central oilice 323, a pair of connective plugs 321 and 322 areconnected together through a repeating rela'y set 323, comprisingrepeating relays 323 and 325 and resistors 323, 321, 323, and

323. Included alsobetween plugs 321 and 322 are a manual key 332 and twoinduction coils 333 and 333 whoseprimary windings are associated with asource of alternating current 35, appear- 3 Line 311-312- has centraloflice equipment 7 comprising a jack 331, a calling relay 352, and

a calling lamp 353, Jack 353 represents another complete line structuresimilar to jack 351 and line 311-312: Preparatory circuits forenergization of repeating relays 323 and 325 include grounded battery,resistor 321, winding of repeating relay 325, contacts of repeatingrelay 323, contacts of key 332', contacts of relay 333and resistor 333to ground, also battery, resistor 323, winding of relay 323, contacts ofrelay 325, contact or double-wound relay 335, and resistor to ground. ir

In operation, closure ofkey 311 energizes calling relay 352 and callinglamp 353 over obvious circuits. An operator at the central oiliceresponds by inserting plug 321 into jack 351, thereby forming circuitsfor both direct current and alternating currents. For direct current,the circuit includes grouniied battery, resistor 321,

winding of repeating relay 323, contacts of ener-.

gized repeating relay 323, contacts 01 key 332, a lowest winding ofinduction coil 333, lower winding of relay 333, ring of plug 321, longspring power is supplemented by alternating current from a central powersupply which is transmitted overthe phantom circuit of the line for bydirect oralternating current, also a further rotor winding 333- andcollecting rings 331 for driving the motor by. alternating current. The

motor is providedalso with a centrifugal switch of Jack 351, lineconductor 312, break key 313, normally closed contacts of permutationtransmitter 313, recorder magnets 315, line conductor 311, short springof jack 331, tip of plug 321, upper winding of relay 333, middle windingof induction coil 333,.contac'ts of key 332, and re-'- sistor 331 toground, energizing relay 333. which closes an obvious circuit toilluminatelamp 3.31. i

For alternating currents, a circuit includes grounded battery, resistor321, winding ofrelay 323, contacts of relay 323, contacts of key 332,

lowest winding .of induction coil 333.as a source of alternating,current, lower winding of relaycurrent relay m, and switch as to ground,also 2,249,435 a companion circuit includes ground, resistor 33lcontacts of key 332, middle winding of induction coil 333 as a source ofalternating current.

spring of jack 35l, line conductor 3| I, condenser 3l3, alternatingcurrent relay H0, and switch 303 to ground, thus energizing relay 310whose contacts connect commutator 334 and rotor winding:

305 to a source of current 382. vThe rotor 303 starts under energyreceived from source 362 andwhen operating speed is reached, thecentrifugal switch 309-operates to include the rings and winding 306 inthe 'circuits for alternating curby two windings of relay 346, by twosecondary windings of induction coil 333 and by resistor 33| balanceda'gainstresistor 32'lrand winding of repeating relay 325.

. An operator at central oflice 320 now may operate key 332 by rotatinga cam 363 through an angle-at 90, thereby connecting receiver magnet 342into the described line and phantom circuits in balanced manner andincluding also contacts of transmittingrelay 345. Thereafter,communication may proceed betweenfloperators set 3 and substation 300.Opening the conntacts of transmitter 3l8 to produce a spacing signaldoes not unbalance the phantom circuit, and opening the contactsoftransmitter 343, to produce a spacing signal, operates relay 345 tosubstitute resistor 344 in place of resistor 32! and winding,

of relay 325 thereby maintaining the phantom circuit in balance.

A connection for intercommunication between two substations is completedby inserting plug 322 into jack 354, energizing relay 365 and illuupperwinding of relay 346, tip of plug 32l, short ductors and minating lamp383. At either connected substa-' tion, the substation operator mayattract attention of the central oilice operator by opening a "break key3l8, deenergizing one o! the doublewound relays 345 and 335 toextinguish one of the signal lamps 341 or 338. Responsively tooperationof a key 3l3, a lamp may be fl hed repeatedly until a centraloflice operator answers.

Other applications of the invention as defined by'the appended claimsmay-be made in full or in part as required to practice the invention toany desired extent.

What isclaimed is:

1. In a telegraph switching system, aswitching station, remote telegraphstations, lines connecting said remote stations to said switchingstation, apparatus at said switching station to seize lines forinterconnecting said remote stations for intercommunication, telegraphsets and driving motors therefor at said remote stations, and means forcompleting over a line to a selected [said substation sets to saidmunication circuit for the telegraph set at the selected station and amotor synchronizing circult including the windings of the motor at theselected station by the'act of seizing a line for communication.

and for completing a telegraph circuitover the selected line for thetelegraph set at the" selected station.

4. In .a telegraph system, substations, telegraph sets at saidsubstations'including synchronous motors, a central oflice includinglineswitching apparatus tointerconnect said substations, a source ofvariable frequency alternating current, communication lines connectingratus, and means at said central oflice to apply over a seized line andthrough a motor at as'elected station a seriesof alternating impulses ofincreasing frequency for starting said motor in response to seizure ofthe line for communication.

5. -In a telegraph system, a telegraphset, a driving motor for saidset,fa line comprising two conductors, both of "said ings of saidincluding ameans including circuits through two conductors and throughwindmotor for starting said motor, means circuit through one of said twoconthrough a circuit of said motor for driving said moto and meansincluding'acircuit through the other of said two conductors foroperating said telegraph set for communi cation. 6. In a telegraphsystem, a telegraph set, a driving motor for said set; ,a loop circuitforv communication with said set,-an alternating current source of powerof frequency higher than the baud value of said and a power circuitincluding conductors ofsaid loop circuit for-altemating power currents'for driving said motor-.1

remote station both a communication circuit for the telegraph set atsaid selected station and a motor operating circuit including thewindings of themotorat said selected station by the' act of seizing thelin forcommunication.

, 2. In a telegraph switching system, a switch ing station, remotetelegraph stations, lines connecting said remote stations to saidswitching station, apparatus at said switching, station to" Y seize aline for interconnecting said remote sta- 7. In a telegraph switchingsystem, a switching station, remote telegraph stations, lines radiatingfromsaid switching station to said remote stations, switching apparatusat said switching station to seize the lines for interconnecting saidremote stations, telegraph sets and driving motors therefor atsaidremote stations, a normally inert motor generator at said centraloffice, and means responsive to seizm'e of a line for communication forstarting said generator and for connecting said generator to the seizedline for applying starting current to a motor at-a remote station oversaid line while said starting motor generator is increasing in' f smed.

- 8. In a telegraph system, a telegraph 'substa tion set having adriving motor, a direct current source 10! powerfor signaling, acommuniq cation line connected to said substation set for direct currentsignaling, an alternating current 1 source of power for drivingsaid-motor, means for transmitting altemalting currents through tions,telegraph sets and driving motorstherefor at saidremote stations, andmeans for completing over a line to a selected station both a comsaidmotor over said communication line, a syn-j I chronizing winding in saidmotor, and means sponsive to motor speed to synchronize said motor bysaid altematingcurrents.

, lines connecting said line-switching appacommunication circuit a 9. Ina telegraph system, a telegraph substation set having a driving motor, adirect current source of power, a'communication line to said substationset, means including said communication line and said source of powerfor direct current telegraph signaling, an alternating current source ofpower, a circuit superposed on said communication line, means fortransmitting alternating currents through said motor over saidsuperposed circuit, and a motor control relay at said substationresponsive to said alternating currents,

10. In a communication system, a central station, a substation, atelegraph set at said substation including a driving motor, a twocondu'ctor communication line connecting said subsubstations, switchingmeans at said central sta-.

tion for interconnecting said lines and substations, cyclicallyoperating means normally inert for starting a motor at a substation,means recalling station has been started, and further automatic meansrendering said cyclically operstation to said centralstation, a sourceof power at said central station, starting circuits for said motorincluding said source of power and the conductors of said communicationline in parallel, means at the central station to seize said line, andmeans responsive to the seizure of said line for communication toconnect said startin circuits to said motor.

11. In a communication system, two stations, a pair of wires connectingsaid stations, a motor and motor driven communication apparatus at eachstation, a power supply at one station, means to transmit power over thetwo wires in parallel to operate the motor at the' other station, andmeans to establish communication between the two said apparatus over thetwo wires in series.

I 12. In a telegraph system, two stations, a pair of wires connecting,said stations, motor driven telegraph'a-pparatus at each station, asource of power at one station having motor speed controllingcharacteristics, means to control the speed of the motor at the otherstation by impulses transmitter from said source of power through .saidmotor over the two wires in parallel, and means to control variably onetelegraph apparatus from the other by impulses transmitted over the twowires in series.

13. In a telegraph system, a central station.

' a remote station, a telegraph set including a ating means again activeto start a motor at a substation selected and connected with forinterconnection with said calling substation.

16. In a telegraph system, a telegraph substation set having a drivingmotor, a driving windingin said motor, a synchronizing winding in saidmotor, a source of power at said substation to drive said, motor, acommunication line connected to said substation set for direct currenttelegraph signaling, a motor control relay, an alternating currentsource of power, means for transmitting alternating currents over saidcommunication line and through said motor control relay to connect saidsource of power at said substation to said driving winding, andmeansresponsive to motor speed to switch alternating currents over saidcommunication line through said synchronizing winding to synchronizesaid motor.

17. In a telegraph system, a central station, a remote station, acommunication line to connect said remote station to said centralstation, telegraph apparatus at said remote station in cluding a drivingmotor, a-source or power at said remote station to drive said motor, acircuit connecting said source of power to said motor, a relay tocondition said circuit, a source of alternating current at said centralstation,

means at said central station to seize a line, and

driving motor at said remote station, a line to Q connect said remotestation to said central station for intercommunication, means at saidcentral station to seize said line to establish a motor control circuitand a telegraph circuit for said remote station, a calling key at saidremote station, a calling signal device at said central station, acalling circuit including said key and said signal device and responsiveto the operation of said key when said line and seizing means aredisengaged, and a switch controlled by said motor to render saidsignaling circuit unresponsive to the operation of said key while saidmotor is in operation and said line is not seized.

14. In a telegraph system, a central station, a remote station, atelegraph set including a driving motor at said remote station, a lineto connect said remote station to said central stationi'orintercommunication, means at said central station to seize said line andcomplete both a motor control circuit and a. telegraph circuit for theset at said remote station, a switch operated by said motor, and aturther circuit including'said switch conditioned upon the disengagementof said seizing means to cause the motor to come to rest in apredetermined condition.

15; In a telegraph system, a'central switching station, a plurality ofsubstations having motors, line! connecting said central station withsaid complete a telegraph circuit for said apparatus and to supplyalternating current over said circult to said remote station to-energizesaid relay and start said motor.

18. In a telegraph system, a substation, a motor and motor drivenapparatus at the substation, a central station, electrical connectionsbetween the central station and the substation, a direct current sourceof power, an alternating current source of power, means including saidelectrical connections to apply direct current to start the motor at thesubstation, means to transmit subsequently over said electricalconnections and through said motor alter'natingcurrent to control thesynchronous operation of the motor, and

' means to establish a communication circuit simultaneously with thebeginning of transmission of the alternating'current.

19. In a telegraph system, telegraph apparatus, a motor to drive thetelegraph apparatus, a telegraph line for the apparatus, a startingcircuit for said motor including said line and a winding of said motor.a running crcuit for said motor, a telegraph circuit for said apparatusincluding said line, a centrifugal device driven by said motor, andmeans controlled by said'cen- 20.111 a telegraph system, two moons,toe-- graph receivers and'driving motors therefor at said stations, atelegraph communication line connecting said two stations, means totransmit telegraph signals over said line, a power source of alternatingcurrent at one of said stations. and circuit means for transmission ofalternating current from said power source over'said telegraphcommunication line to the motor of the other of said stationsindependently of said communication signals.

circuits over the other of said lines to said necting said remotestation and said central station, a telegraph set at said remote stationincluding a driving motor, a first source of power and a second sourceof power at said central station, a starting circuit for said motorinclud- 21. In a telegraph system, a central station, 10 ing said firstsource of power and said two conremote telegraph stations, telegraphsets and driving motors therefor at said remote stations, linesconnecting said remote stations to said central station, apparatus atsaid central station to seize said lines, an alternating current powersupply at said central station, and means respon-, sive to the seizureof a line to complete a telegraphcircuit over said line to a remotestation and to connect said supply over said line to the motor at saidremote station to start said motor.

22. In a telegraph switching system, a switcha ing station, linesradiating from said station.-

switching apparatus at said station for seizing said lines forcommunication, telegraph sets and driving motors therefor on said lines,a source of alternating current at said switching station, and meansembodied in said switching apparatus at said station for forming acommunication circuit for a telegraph set over conductors of a seizedline and for supplying synchronizing alterhating current from saidsource over said-conductors to the winding of the driving motor of saidI telegraph set on said seized line.

23. In a communication system, a telegraph set including a drivingmotor,a communication line connected to said set, a source of power, a

first circuit to said set including said line for communicationsignaling, and a second circuit to said set superposed on said firstcircuit, said second circuit including said motor, said line, and saidsource of power to control said motor.

24. In a telegraph system, a telegraph loop, telegraph communicationapparatus connected in said loop, a motor for driving said apparatushaving a synchronous winding, a circuit for said synchronous windingincluding line conductors of said loop, an auxiliary starting winding insaid motor, a circuit for said starting winding'includ- ,ing a conductorin said loop, and a centrifugal thereafter maintaining the speed 01'said motor,

and 'meansincluding the other of said conductors for operating saidtelegraph set for communication.

26. In a telegraph system, a central station,

a plurality of substations having telegraph sets and driving motors, aplurality of two conductor telegraph lines connecting said centralstation and said substations, a polyphase generator at said centralstation, starting circuits each including a motor and the two conductorsof one of said telegraph lines connecting said motors to said generator,and means for rimning said motors subsequently over but one of saidconductors in ductor line, a running circuit for said motor includingsaid second source of power and one line, and means to disconnect saidstarting circuit and to 'connect said running circuit and said telegraphcircuit to said telegraph set at said remote station after said motorhas started.

28. In a telegraph system, a substation, motor driven telegraphapparatus at the substation, a

. central station, a directcurrent source of power, 1 I an alternatingcurrent source of power, telegraph loop connections between the centralstation and the substation including two conductors, means to transmitdirect currentthrough said motor and over both conductors in parallel01. said telegraph loop connections to start the motor, and means tosubsequently transmit over both conductors in parallel of said telegraphloop connections alternating, .current for synchronously operating saidmotor during operation of said telegraph loop for telegraphy bycommutated direct current.

29. In a telegraph system, a substation, motor driven telegraphapparatus at the substation, a central station, a direct current sourceof power, analternating current source of power, telegraph loopconnections between the central station and the substation, meansincluding first circuits superposed on said telegraph loop connectionsto apply direct current through the motor to start the motor at thesubstation, and means to transmit over second circuits superposed onsaid telegraph loop connections alternating current motor has attainedsubstantially synchronous speed to establish an alternating-currentmotordriving-power circuit over a phantom circuit upon said two wires,andto establish a telegraph loop circuit upon said two wires for communication by commutated direct current,

31. In a telegraph system, a central ofiice, two telegraph substations,two-conductor lines connecting said substations to said central ofilce,

substations for intercommunicatlon, means including circuits through asingle conductor of each' of said lines and through said motors formaintaining said motors in synchronism with each other including meansfor connecting said substations through said one conductor'of eachotsaid lines and for completing telegraph I said line circuits to saidsource of alternating current at said central oifice, further meansincluding both conductors or said two-conductor lines for starting saidmotors one at a time in the order that their lines have been seized atsaid central omce, and automatic means to connect a started motorthrough one vconductor of a line to said first mentioned means, and toconnect the other conductor to said telegraph apparatus. v

32. In a communication system, a plurality of substations, motors ateach substation, a central station, two-conductor lines connecting saidsubstations to said central station, means at said central station toseize said lines for intercommunication, means including both conductorsof one of said lines in series with amotor to start and bring to apredetermined speed one by one a plurality of said motors, inthesequence in which their lines have been seized, independent 3 by saidmotors, and means to connect said telegraphic apparatus to theotherconductor of a line only when said independent means is in operatedcondition.

33. In a telegraph system, a central station, a remote station, a linecomprising two conductors to connect said remote station and saidcentral station, a telegraph set and driving motor therefor at saidremote station, means at said central station to seize said line andestablish over said hne a motor operating circuit and a telegraphcircuit for said set at said remote station, a callsignal circuitextending between said remote station and said central station, andmeans at said substation controlled by said motor to disconnect saidtelegraph set trom said line and.

and a power circuit including-said communicaw tion line conductor, saidmotor, and said cam switch for propelling said armature into apredetermined angular position and for operating 35. In a telegraphsystem, a central station telegraph set, a plurality of substationtelegraph sets having telegraph apparatus and. driving said centralstation telegraph set with one of said substation sets forintercommunication,

said cam switch to prepare said call-signal circuit, said power circuitbeing operable when said communication line is disconnected from saidswitching equipment,

cyclically operating means normally inert for starting a motor of asubstation set over a circuit including one of said lines, meansresponsive to the act or connection with a substation set for renderingsaid cyclically operating means active to start a motor of a selectedsubstation set, and automatic means for establishing a driving circuitincluding a line conductor for said started motor, for establishingintelligence communicative conditions for the selected telegraphapparatus thereof and for restoring said cyclically operating means toinert condition after starting a motor.

36. In a telegraph system, a central station, a remote-station, a twoconductor line to connect said remote station and said central station,a

telegraph set at said remote station including a driving motor, agenerator at said central station normally inert, means at the centralstation to seize the line, a starting circuit including said twoconductor line and said generator, means responsive to the act ofseizing a line to condition said starting circuit and to operate saidgenerator to start'said motor at said remote station, and meanssubsequently operable to establish a running circuit for said motorincluding one conductor of said line and to establish a telegraph.circuit for said set at said remote station.

37. In a communication system, a substation, motor driven apparatus atthe substation, a central station, electrical conductors between thecentral station and the substations, a source of direct current power, asource of alternating current power, means including said electricalconductors to apply direct current to said conductors to start the motorat the substation,

and means to transmit thereafter concurrently over said electricalconductorscommutated direct current for intelligence signaling andalternating current to control the synchronous operation oi the motor. 1

38. -In a communication system, a communica-

